El Nino May Cool U.S. This Summer, Cutting Electricity Demand

The possibility of an El Nino, a warming of the mid-Pacific Ocean, has forecasters predicting lower temperatures across the U.S. this summer, which may mean less electricity will be needed to run air conditioners.

May will probably be warmer than normal, and then “we are expecting a much different type of pattern” than last year, said Todd Crawford, chief meteorologist at Weather Services International in Andover, Massachusetts.

Commodities traders watch temperature outlooks to gauge energy use and demand. About 51 percent of U.S. households use natural gas for heating, according to the Energy Department, while demand from electricity generators peaks in the summer months to meet air conditioning needs.

June through August 2011 was the second-warmest summer on record in the contiguous U.S., with an average temperature of 74.5 degrees Fahrenheit (23.6 Celsius), 2.4 degrees above the 1901-2000 average, according to the National Oceanic and Atmospheric Administration. The hottest summer in records going back to 1895 was 1936, with an average temperature of 74.6.

“The combination of an emerging El Nino event, expectations for relatively muted levels of atmospheric blocking and a cooler North Atlantic all suggest a milder summer,” he said.

Texas Cooldown

Crawford said the South, especially Texas, will be notably cooler than last year. Texas had the hottest summer of any U.S. state in 2011, with an average temperature of 86.9 degrees, according to NOAA. The previous high was in Oklahoma in 1934, with an average temperature of 86.5 degrees.

Last year, a La Nina ocean cooling pattern held sway in the central Pacific, contributing to warmer and drier weather across the U.S. South. La Nina ended this month, according to a statement today by the Australian Bureau of Meteorology.

Some computer models suggest an El Nino may replace the current neutral conditions in the Pacific and that may cause the summer to be cooler, said Matt Rogers, president of the Commodity Weather Group LLC in Bethesda, Maryland.

Rogers said there is a 40 percent chance that the eastern U.S. will be about 1 degree above normal from June to August and a 35 percent chance it will be 2 to 3 degrees cooler.

Crawford said if the El Nino does develop, the hottest part of the summer will be its start, with cooler weather arriving as the season wears on.